The Alien Infantry Caste is a caste of aliens that can be identified by their lack of grasping hands; instead, they have a weapon grafted onto each arm. Their average height is about 8'1". As of the initial invasion, they are estimated to be the most abundant caste, numbering about 25 million in total. It appears that they are deployed in columns, lead by a non-specialized officer.
Like the other castes, the heads of Alien Infantry soldiers are nothing but sensory organs. All of their vital organs are concentrated behind layers of muscle and arteries in the right of their chests. A cooling system is also integrated into their body, with a heat-dispersing fan located in front of their organs. Unlike many of the other castes, they do not have as much machinery located on their back.